Influence of environmental factors on 2,4-dichlorophenoxyacetic acid degradation by Pseudomonas cepacia isolated from peat.

A Pseudomonas cepacia, designated strain BRI6001, was isolated from peat by enrichment culture using 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole carbon source. BRI6001 grew at up to 13 mM 2,4-D, and degraded 1 mM 2,4-D at an average starting population density as low as 1.5 cells/ml.

Alcohol education courses for offenders: an update on U.K. services.

Current service provision for offenders through Alcohol Education Courses (AECs) was examined. Information from fifty-five British agencies was collected, showing differences between AECs offered with respect to clients, teaching components and evaluation. More agencies now collect post-intervention follow-up data on clients' drinking/offending behaviour.

Intron sequence and structure requirements for tRNA splicing in Saccharomyces cerevisiae.

Predicted single-stranded structure at the 3' splice site is a conserved feature among intervening sequences (IVSs) in eukaryotic nuclear tRNA precursors. The role of 3' splice site structure in splicing was examined through hexanucleotide insertions at a central intron position in the Saccharomyces cerevisiae tRNA gene. These insertions were designed to alter the structure at the splice site without changing its sequence.

Copy number and stability of yeast 2 mu-based plasmids carrying a transcription-conditional centromere.

For certain yeast plasmids, the presence of a centromere segment (CEN) enhances mitotic stability and results in low copy number. Transcription from an inducible promoter adjacent to a CEN segment has been shown to alter centromere function. The rate of loss of a conditional CEN-ARS plasmid was examined and the results suggest that segregation control was immediately and effectively inactivated upon shift to inducing conditions.

Prevention of nosocomial transmission of respiratory syncytial virus in a newborn nursery.

During three winter seasons prior to 1984-1985 the special care nursery at New England Medical Center experienced respiratory syncytial virus (RSV) epidemics that required closure of the unit. Prior to and during the 1984-1985 winter season, several measures were taken to prevent recurrent nosocomial RSV transmission. In the winters of 1984-1985 and 1985-1986 there were 26 introductions of community-acquired RSV with no transmission of nosocomial cases during 1,688 patient days at risk as compared with 1983-1984 when there were seven cases of nosocomial RSV following six introductions of RSV during 875 patient days at risk (rate = 8 per 1,000 patient days) (P = 0.

The effect of intravenous tissue-type plasminogen activator in a rat model of embolic cerebral ischemia.

Thrombolytic agents may be useful in the treatment of cerebral ischemia caused by arterial thrombosis or embolic occlusion. A trial of intravenous human tissue-type plasminogen activator (rt-PA) was carried out in seven male Sprague-Dawley rats subjected to embolic cerebral ischemia, with eight control animals. One-hour-old autogenous blood clot was injected into the internal carotid artery.

Golgi analyses of dendritic organization among denervated olfactory bulb granule cells.

In the vertebrate olfactory bulb, the primary projection neurons, mitral and tufted cells, have reciprocal dendrodendritic synapses with respective subpopulations of anaxonic interneurons called granule cells. In the neurological murine mutant Purkinje Cell Degeneration (PCD), all mitral cells are lost during early adulthood. As a consequence, a subpopulation of granule cells is deprived of both afferent input and efferent targets.

Plasticity of dendrodendritic microcircuits following mitral cell loss in the olfactory bulb of the murine mutant Purkinje cell degeneration.

Mitral cells of the olfactory bulb typically form reciprocal dendrodendritic synapses with anaxonic interneurons, granule cells, within a sublamina of the external plexiform layer. As a result of mitral cell loss in the murine mutant Purkinjie cell degeneration (PCD), subpopulations of these granule cells are denervated. The present report examines the capacity of these denervated interneurons to form new dendrodendritic microcircuits with a second population of olfactory bulb neurons, tufted cells.

Substrate recognition and identification of splice sites by the tRNA-splicing endonuclease and ligase from Saccharomyces cerevisiae.

We have examined the substrate requirements for efficient and accurate splicing of tRNA precursors in Saccharomyces cerevisiae. The effects of Schizosaccharomyces pombe tRNASer gene mutations on the two steps in splicing, intron excision and joining of tRNA halves, were determined independently by using partially purified splicing endonuclease and tRNA ligase from S. cerevisiae.

Automated colorimetric assay for the detection of Pasteurella haemolytica leucotoxin.

A rapid and easily performed colorimetric method has been adapted for the detection of the Pasteurella haemolytica leucotoxin using the lysis of bovine leucocyte BL-3 cells (a bovine lymphoid cell line obtained from Dr. G. Theilen, University of California, Davis).

Assembly of a tRNA splicing complex: evidence for concerted excision and joining steps in splicing in vitro.

Splicing of tRNA precursors in Saccharomyces cerevisiae extracts proceeds in two steps; excision of the intervening sequence and ligation of the tRNA halves. The ability to resolve these two steps and the distinct physical properties of the endonuclease and ligase suggested that the splicing steps may not be concerted and that these two enzymes may act independently in vivo. A ligase competition assay was developed to examine whether the excision and ligation steps in tRNA splicing in vitro are concerted or independent.

Cloning and expression of the leukotoxin gene of Pasteurella haemolytica A1 in Escherichia coli K-12.

A clone bank of Pasteurella haemolytica A1 was constructed by partial digestion of the genomic DNA with Sau3A and ligation of 5- to 10-kilobase-pair fragments into the BamHI site of the plasmid vector pBR322. After transformation into Escherichia coli K-12, a total of 4 X 10(3) recombinant clones was obtained. These were screened for the production of P.

High-resolution 2-deoxyglucose autoradiography in quick-frozen slabs of neonatal rat olfactory bulb.

We have used rapid freezing and freeze-substitution fixation to permit electron microscopic study of [3H]2-deoxyglucose autoradiographs. The techniques minimize diffusion of label into processing fluids and, by inference, migration of label within tissue. Slabs of olfactory bulbs from 12-day-old rats were quick-frozen after one hour of exposure to physiological olfactory stimuli.

Hemiazygous continuation of a left inferior vena cava: misleading radiographic findings in chest trauma.

A widened mediastinum was found on chest radiography following blunt chest trauma. Aortography alone could not adequately determine the etiology of the radiographic findings; on computed tomography (CT) benign mediastinal widening was confirmed owing to accessory hemiazygous continuation of a left inferior vena cava (IVC), with communication to the left brachiocephalic vein through an enlarged left superior (highest) intercostal vein. This unusual anatomic variant and its radiographic findings are reviewed, as well as the complementary role of CT in the evaluation of the traumatized thoracic aorta and mediastinum.

Specific olfactory receptor populations projecting to identified glomeruli in the rat olfactory bulb.

A critical gap exists in our knowledge of the topographical relationship between the olfactory epithelium and olfactory bulb. The present report describes the application to this problem of a method involving horseradish peroxidase conjugated to wheat germ agglutinin. This material was iontophoretically delivered to circumscribed glomeruli in the olfactory bulb and the characteristics and distribution of retrogradely labeled receptor cells were assessed.

Medical illness in chronic psychiatric outpatients.

A careful physical and laboratory evaluation of 144 chronic psychiatric outpatients revealed medical illnesses in 26%. Chart review indicated that 13% of the patients had illnesses that were previously undetected and that 13% of the patients received some form of new treatment because of the evaluation. The majority of the illnesses did not appear to have directly caused or exacerbated psychiatric symptoms.

Evidence for olfactory function in utero.

Pregnant rats received 2-[14C]deoxy-D-glucose (2DG) intravenously on the last day of gestation, and their fetuses were delivered 1 hour later by cesarean section. Fetal brains showed high 2DG uptake spread throughout the accessory olfactory bulb and little or no differential uptake in the main olfactory bulb. These findings demonstrate that functional activity occurs in the accessory olfactory bulb in utero and suggest that the accessory olfactory system may be the pathway by which fetal rats detect the odor quality of their intrauterine milieu.

Enzymatic mechanism of an RNA ligase from wheat germ.

We have characterized the mechanism of action of a wheat germ RNA ligase which has been partially purified on the basis of its ability to participate in in vitro splicing of yeast tRNA precursors (Gegenheimer, P., Gabius, H-J., Peebles, C.

RNA ligase in bacteria: formation of a 2',5' linkage by an E. coli extract.

Ligase activity was detected in extracts of Escherichia coli, Clostridium tartarivorum, Rhodospirillum salexigens, Chromatium gracile, and Chlorobium limicola. Ligase was measured by joining of tRNA halves produced from yeast IVS-containing tRNA precursors by a yeast endonuclease. The structure of tRNATyr halves joined by an E.

The effect of intranasal zinc sulfate treatment on odor-mediated behavior and on odor-induced metabolic activity in the olfactory bulbs of neonatal rats.

This study describes the effect of lesions of the peripheral olfactory receptor sheet on odor-mediated behavior and on odor-induced metabolic activity in the neonatal olfactory bulb. Nine-day-old rats were treated by intranasal irrigation with a solution of 1% ZnSO4 or 5% ZnSO4 or saline. At 1 and 5 days following treatment they were tested for maternally-directed behaviors which are mediated in large part by olfactory cues.

Laminar distributions of 2-deoxyglucose uptake in the rat spinal cord following electrical stimulation of the sciatic nerve.

The 2-deoxyglucose method was employed to study the functional organization of afferent axons in the dorsal horn of the rat spinal cord. Stimulation of axons in the sciatic nerve with conduction velocities greater than 17 m/s produced activity predominantly in the deep laminae of the dorsal horn. In contrast, stimulation of the entire population produced activity throughout the dorsal horn.